Hellenic journal of nuclear medicine最新文献

Primary perivascular epithelioid cell tumors (PEComas) originating in the pericardium are extremely rare. We present a rare case of a malignant PEComa arising from the pericardium, with abnormal fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) uptake maximum standardized uptake value (SUVmax 23.1) on positron emission tomography/computed tomography (PET/CT) scan, indicating its highly aggressive nature. Imaging revealed a soft tissue mass in the left atrial appendage with poorly defined borders to adjacent structures. The patient underwent CT-guided biopsy, and histopathological examination confirmed the diagnosis of malignant PEComa. This case underscores the atypical imaging features of a malignant pericardial PEComa, which, due to its elevated ¹⁸F-FDG uptake, should be considered in the differential diagnosis of cardiac masses with similar PET/CT characteristics, as well as for distinguishing between benign and malignant lesions.

Objective: This study investigated the diagnostic test accuracy of fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) based radiomics features for prediction of programmed cell death protein 1 and its ligand (PD-L1) expression in non-small cell lung cancer (NSCLC).

Materials and methods: A systematic search was performed in PubMed and EMBASE (last updated in 31 August 2024). Studies evaluating diagnostic performance of ¹⁸F-FDG PET/CT based radiomics features for prediction of PD-L1 expression in NSCLC. The sensitivities, specificities, positive and negative likelihood ratios (LR+ and LR-), and pooled area under curve (AUC) were estimated.

Results: The pooled sensitivity of ¹⁸F-FDG PET/CT was 0.75 (95% CI; 0.64-0.83) and a pooled specificity of 0.66 (95% CI; 0.52-0.78) for prediction of >1% expression of PD-L1. For prediction of >50% expression of PD-L1, the pooled sensitivity of ¹⁸F-FDG PET/CT was 0.77 (95% CI; 0.67-0.85) and a pooled specificity of 0.61 (95% CI; 0.55-0.66). For >1% expression of PD-L1, the pooled AUC of fixed effects was 0.791 (95% CI; 0.771-0.811) and of random effects was 0.783 (95% CI; 0.722-0.845). For >50% expression of PD-L1, the pooled AUC of fixed effects was 0.735 (95% CI; 0.718-0.751) and of random effects was 0.766 (95% CI; 0.706-0.825).

Conclusion: Analysis of the available studies indicated that ¹⁸F-FDG PET/CT based radiomics features showed a moderate diagnostic performance for prediction of PD-L1 expression in NSCLC. However, future studies would be necessary for standardization of the method for prediction of PD-L1 expression in NSCLC using ¹⁸F-FDG PET/CT based radiomics features.

We present a case that illustrates the very rare occasion of isolated pulmonary metastases in a prostate cancer patient, confirmed in the prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT), along with the rapid rise of the prostate specific antigen (PSA), following cessation of Darolutamide.

Objective: Lymph node (LN) staging in lung cancer is crucial for treatment decisions. To develop and validate a positron emission tomography/computed tomography (PET/CT) radiomics model for preoperative estimation of LN metastasis in non-small cell lung cancer (NSCLC).

Subjects and methods: A retrospective analysis of 252 NSCLC patients with 548 pathologically confirmed LN, including 227 occult LN, was performed. Clinical and PET/CT features were collected. Eight machine learning models were used for feature selection and radiomics signature (R-signature) construction. Models were developed for both the overall and occult LN groups. Model performance was evaluated using area under the curve (AUC), calibration, and decision curve analysis.

Results: The random forest-enhanced logistic regression (RFELR) model, based on 20 features, showed the best performance in predicting LN metastasis in both groups. The combined model demonstrated the highest predictive efficacy, with AUC of 0.94 (overall LN) and 0.89 (occult LN) in the training cohort, and 0.95 (overall LN) and 0.78 (occult LN) in the validation cohort. The combined model outperformed clinical, CT, and PET models (P<0.05) in both cohorts. Decision curve analysis showed a greater net benefit across a wider range of threshold probabilities for LN metastasis prediction.

Conclusion: The combined model, integrating clinical, conventional PET/CT, and radiomics features, significantly enhances LN metastasis diagnosis. It shows promise in predicting occult LN metastasis and offers valuable support for personalized therapeutic decisions in NSCLC patients.

Objective: To investigate the determinants of cure after radioactive iodine (RAI), a treatment frequently used to treat Graves' thyrotoxicosis.

Materials and methods: We conducted a retrospective analysis of data from 160 consecutive patients with Graves' thyrotoxicosis who received 370MBq of iodine-131 (¹³¹I) at one centre between 2009 and 2018. Data included gender, age, cause of thyrotoxicosis, and number of RAI doses administered. Free thyroxine (fT4) and triiodothyronine (fT3) level at diagnosis, thyroid stimulating hormone (TSH), fT4 and fT3 levels on the day of RAI, and TSH, fT4 and fT3 at 3, 6, and 12-months post RAI treatment were reviewed. Cure was defined as achieving a euthyroid or hypothyroid state within one year of RAI administration.

Results: Eighty one percent of the total cohort achieved cure at one year. Sixty one point eight percent of patients developed hypothyroidism within one year necessitating lifelong thyroxine replacement. fT4 at diagnosis (P=0.02), fT3:fT4 ratio at diagnosis (P=0.05) and the ratio of fT4 at diagnosis to fT4 pre-RAI ratio (P=0.05) and fT4 pre-RAI (P=0.002) were independent variables associated with cure after one year.

Conclusion: Radioactive iodine is a highly effective treatment for Graves' thyrotoxicosis. It is more likely to be successful in patients with lower fT4 at diagnosis and pre-RAI.

The integration of artificial intelligence (AI), particularly large language models (LLM), into medical research writing is reshaping the landscape of academic authorship, productivity, and scholarly merit. It has been demonstrated that LLM are capable of greatly expediting the process of researching, drafting, and publishing manuscripts, despite current limitations currently necessitating intensive human oversight to ensure veracity and mitigate the phenomenon of "hallucination". With these limitations being addressed by AI developers and perhaps on their way to irrelevance, a different question emerges as the most, and perhaps only, important one. This paper adopts a first-principles ethical approach to examine the core moral question: independent of technological feasibility, to what extent is it ethically permissible to use AI in the drafting of medical research? We argue that the ethical imperative to accelerate scientific discovery, especially in Medicine, outweighs traditional concerns about the mechanics of authorship and merit attribution. Drawing on Aristotelian teleological reasoning, we contend that the primary value of research lies not in the process of its composition but in its capacity to alleviate suffering and advance human knowledge. Further, we understand authorship as inherently human, as only humans possess the moral agency required to accept responsibility for their work, which is something AI, by its nature, lacks. The paper concludes with a set of normative recommendations to guide the responsible and transparent integration of LLM in research.

Objective: Fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) is widely used in lymphoma for diagnosis, interim evaluation, and treatment response assessment, utilizing both visual and semiquantitative analyses. However, factors such as image reconstruction algorithms may influence maximum standardized uptake value (SUVmax), mean SUV (SUVmean), and Deauville scores. This study aims to evaluate the impact of ordered subset expectation maximization (OSEM) and Q.Clear reconstruction methods on these parameters in lymphoma patients.

Materials and methods: This study included 48 patients diagnosed with lymphoma who underwent ¹⁸F-FDG PET/CT imaging between January 1 and April 12, 2024, for interim evaluation, post-treatment assessment, or relapse investigation. Positron emission tomography data were reconstructed using OSEM and Q.Clear algorithms, routinely applied in our clinic. The lymph node with the highest SUVmax in each scan was selected as the target lesion. Additionally, subcentimetric lymph nodes (<1cm) were analyzed to assess the impact of reconstruction algorithms on detectability. Maximum SUV and SUVmean values of the liver and mediastinal blood pool were also recorded for Deauville scoring. Statistical analyses were conducted to evaluate significant differences between the two reconstruction methods.

Results: Liver and mediastinal blood pool SUVmax values were significantly higher with OSEM, while SUVmax values of both <1cm and >1cm lesions were higher with Q.Clear. For SUVmean, OSEM yielded higher values in the mediastinal blood pool, while Q.Clear showed higher values in lesions >1cm. Deauville 4-5 scores were more frequent with Q.Clear in both lesion size groups.

Conclusion: This results refers to the comparative use of ¹⁸F-FDG PET/CT imaging with different reconstruction algorithms in treatment response evaluation . and restaging changes to the standardization and that caution should be exercised in the DS evaluation based on semiquantitative values. This leads to a challenge in single and multicenter comparative evaluations with PET/CT scanners using different reconstruction algorithms including digital systems. In this study, we have shown that the reconstruction algorithms used in digital PET/CT devices cause changes in Deauville scoring in patients diagnosed with lymphoma. Therefore, it is important to perform ¹⁸F-FDG PET/CT imaging with the same reconstruction algorithms under standardized conditions or to take this into consideration if not done.

Objective: Gated myocardial perfusion imaging (GMPI) is a cornerstone non-invasive tool for diagnosing and risk stratifying patients with suspected or known coronary artery disease (CAD). Stress-only protocols are advocated in guidelines due to reduced radiation exposure and cost, but long-term data on the absence of major adverse cardiac events (MACE) in a large cohort is valuable. This study aimed to evaluate the long-term outcomes in a large cohort of patients who underwent a normal stress-only myocardial perfusion imaging (MPI) and had no major adverse cardiac events over a 5-year follow-up period.

Subjects and methods: We retrospectively analyzed data from 1000 consecutive patients referred for MPI due to symptoms of stable CAD between 21/05/2018 and 21/7/2025. All patients underwent a stress-only MPI protocol. Only patients with visually interpreted normal stress scans were included in the analysis. The primary endpoint was the occurrence of major adverse cardiac events (MACE), defined as cardiac death or non-fatal myocardial infarction (MI), as ascertained through telephone interview and standardized follow-up over a median of 5 years.

Results: The study population included 1000 patients (mean age: 65.4±10.7 years), (43.4% male). All patients had normal stress-only myocardial perfusion scans. During the median 5-year follow-up period, no major adverse cardiac events (cardiac death or MI) were recorded using telephone interviews across the entire cohort. The annualized cardiac event rate was 0%, reinforcing previously reported low event rates of less than 1% per year for normal studies.

Conclusion: In this large cohort of patients presenting with symptoms of stable CAD who had normal findings on GMPI, the complete absence of major adverse cardiac events over a 5-year follow-up period (only one experienced 1 vessel coronary artery disease 6 years post GMPI) confirms the robust negative predictive value of this imaging modality. These findings support the use of a normal stress-only protocol for identifying a very low-risk patient population in whom further aggressive diagnostic workup may not be necessary.

Objective: To develop a fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography (PET) radiomics-based nomogram model for predicting progression-free survival (PFS) in locally advanced cervical squamous cell carcinoma (LACSC) patients undergoing concurrent chemoradiotherapy (CCRT).

Subjects and methods: A retrospective study included 241 LACSC patients treated with CCRT, divided into training (n=168) and validation (n=73) sets. Lesion segmentation, radiomics feature extraction and screening were performed on ¹⁸F-FDG PET images of each patient, and radiomics scores (Rad-scores) were calculated.Univariate and multivariate Cox regression analyses were used to identify independent prognostic factors and create a combined model and nomogram. Predictive performance was assessed using time-dependent receiver operating characteristic (ROC) curves, area under the curve (AUC), and consistency index (C-index). Calibration curves evaluated nomogram accuracy, and decision curve analysis (DCA) assessed nomogram clinical applicability.

Results: The Rad-score calculated from five optimal radiomics features and FIGO stage were independent predictors of PFS in LACSC patients.The C-index values for the FIGO stage, Rad-score, and combined model were 0.586, 0.692, and 0.727 in the training set, and 0.612, 0.668, and 0.698 in the validation set, respectively. The combined model showed excellent predictive ability for PFS at 12, 18, and 24 months, with training set AUCs of 0.805, 0.738, and 0.719, and validation set AUCs of 0.670, 0.744, and 0.741, respectively. The calibration curves confirmed a good agreement between predicted and actual progression probabilities, with DCA revealing significant clinical net benefits.

Conclusion: The ¹⁸F-FDG PET radiomics-based nomogram effectively predicted PFS in LACSC patients and could support individualized treatment decisions and accurate prognostic evaluations.

Objective: To analyze the relationship between fluorine-18-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography/computed tomography (PET/CT) and ultrasound breast imaging reporting and data system (BI-RADS) classification, and to evaluate the diagnostic value of their combined application in breast diseases.

Subjects and methods: A retrospective analysis was conducted on the ¹⁸F-FDG PET/CT images and ultrasound BI-RADS classification data of 110 patients with suspected breast cancer treated at our hospital from July 2020 to May 2022. Pearson correlation analysis was used to assess the relationship between the maximum standardized uptake value (SUVmax) and BI-RADS classification. Using pathology or long-term follow-up results as the "gold standard," the diagnostic value of ¹⁸F-FDG PET/CT, ultrasound BI-RADS classification, and their combined application in breast diseases was analyzed.

Results: Based on the "gold standard" of pathology or long-term follow-up, of the 110 patients with suspected breast cancer, 49 were benign, and 61 were malignant. The SUVmax levels of malignant lesions were significantly higher than those of benign lesions (P<0.05). Pearson correlation analysis indicated a low correlation between SUVmax and ultrasound BI-RADS classification (r=0.458, P<0.05). Receiver operating characteristic (ROC) curve analysis showed that the area under the curve (AUC) of the combined application of SUVmax and ultrasound BI-RADS classification was higher than that of either method alone, both for breast tumors and for patients classified as BI-RADS category 3 to 4.

Conclusion: The correlation between SUVmax and ultrasound BI-RADS classification is low (r=0.458), indicating that these two methods assess different biological aspects of breast tumors. However, the combined use of SUVmax and BI-RADS classification significantly enhances diagnostic accuracy, particularly for patients with BI-RADS 3 to 4 lesions. Although this combination improves diagnostic efficacy, ¹⁸F-FDG PET/CT should not be used as a primary screening tool but rather as a complementary method in specific clinical scenarios where imaging findings are inconclusive or suspicion of malignancy is high.